the science behind the beauty

product order & penetration

If you’re a product junkie, like me, you’ve most likely mastered the art of laying skin care and makeup products. You know that the general order for skin care products is cleansing then applying products from thinnest to thickest formulation. When applying makeup products start with a primer, then do the eyes, the face, and finish with the lips. And if you didn’t know all of this before now you do!

Of course being a beauty science blog I’m here to investigate exactly why these products have to be applied in a certain order to be effective. I would like to apologize ahead of time for using the p work so much in this article, it’s unavoidable for me to not use the word penetration when talking about product order and effectiveness. It makes me cringe just as much as the next person.

skin composition

Starting with the basics; our skin has many layers made up of cells, and when cosmetics are applied to it the penetration of the cosmetic can be measured by how far within our skin they reach. There are three layers that our skin has, the first being the epidermis. The epidermis is the outermost layer of skin that most all cosmetic product (maybe aside from makeup products) penetrate. The epidermis or stratum corneum, while it is technically dead, it’s the water barrier, shows our skin color and tone, and the thickness varies throughout our body. The second layer, the dermis, is the middle layer where oil, hair and sweat glands are found. This would be the level where when oil glands get clogged acne would be formed. Finally the third layer, the hypodermis is the connecting and fat layer. Our skin will lose fat over time and as it becomes more detached from our bones and muscle our skin can sag.

skin penetration

Upon conducting research for this post I came across an article from the Beauty Brains that describes the “4 Factors that Control Skin Penetration”. The first is “size and/or molecular weight“ like I said previously, the epidermis (the top layer of skin) is basically a collection of dead cells. Some molecules are too large to fit past these dead skin cells and penetration into our skin, which is why exfoliating weekly is so important! “Oil versus water solubility” is the second component that must be considered. The fat layer of our skin (hypodermis) is composed of lipids (aka fats) which are hydrophobic, technically making our skin “waterproof”, so oil based products will penetration the skin more. Thirdly the “polarity/charge” of the molecules must be taken into account. This is a much more difficult concept to grasp and isn’t necessarily something a consumer would be able to know from an ingredient list, but it’s just considered the polarity of a molecule to understand how effective it will be penetrating the skin. Polarity is essentially the charge balance of molecules based on its structure. Finally “condition of the skin” is extremely important when looking at product penetration. Like I talked about early, the thickness of our skin varies throughout our face, for example, the skin around our eyes is the thinnest on our face. This is why eye treatments are typically super concentrated, in order to target the issue.

While there is obviously a lot more technical science behind how and why different product penetrates our skin differently, I hope you all learned a bit of the basics!